1. Field of the Invention:
The present invention pertains to optic measuring and testing equipment and in particular to a rotating beam of monochromatic light, i.e., laser beams, and which are detected by a photocell.
2. Description of the Prior Art:
This invention relates to a laser beam reference plane instrument of the kind used in the surveying and construction industries. This unique design allows it to be added to conventional optical instruments used in these industries and functions to provide a laser light plane to be used as an accurate positional reference when detected by portable electronic detectors.
The laser beam reference instrument of the present invention is constructed to be used as a replacement for optical means of establishing a positional reference now used in the surveying and construction industries.
Laser beam reference instruments are instruments which sweep a laser beam in a plane and are used in surveying and construction industries. The tube type gas lasers were often used as the light source and the output was deflected by sets of reflecting surfaces and lenses which sweep or swing to produce a plane of light. U.S. Pat. No. 4,062,634 to Rondo et al, gives a detailed description of a prior art laser device which uses a gas tube as a laser light source. U.S. Pat. No. 4,221,483 to Rondo gives a detailed description of a prior art solid state laser establishing a reference plane as applied to a class of instruments designed to be level instruments. Both of these prior art patents are related to a horizontal reference plane and as a self contained unit. The present invention can be used either as a horizontal or vertical reference plane.
The present invention uses a solid state laser source which allows for a much smaller, lighter weight instrument for more portability. The prior art solid state laser instruments maintain the use of many of the optical path techniques used with the gas tube laser instruments (i.e., an assembly of rotating reflective surfaces associated with a system of lenses to produce a reference plane for a non-rotating laser light source). Even with the reduction of size and weight of the prior art solid state laser beam instruments, they are still much too large to incorporate into conventional optical surveying instruments such as a transit level used in the surveying and construction industries without changing or complicating their function beyond the state of the art of their conventional or accepted common usage. The present invention so reduces the size and weight of the laser reference plane generating instrument that it can be mounted on an instrument such as a transit level and will supply a vertical reference plane of laser light in line with the optics without interfering with its original operation.
Whenever a building is to be constructed on a given plot of land, surveying instruments such as an optical level or a transit level are used to sight the corner points for the foundation of the structure to be erected on the given plot of land. An optical level which is sometimes called a dumpy level or a builder's level is placed upon a tripod and the optical level is fixed in a horizontal position. It can be used only for measuring horizontal angles because it cannot be tilted up and down. The telescope of the transit level can be moved up and down as well as sideways. Because of its vertical movement, the transit level can be used to determine if a wall is plumb, measure vertical angles, or run straight lines. The present invention is attached to either a transit level or an optical level by means of a bracket with the invention in a fixed position above the sighting telescope. The transit or optical level is set up over a reference point which can be the corner of a building or another predetermined reference point. The point over which the level is directly centered is called the station mark. This is the point from which the layout is to be sighted or shot. The tripod is centered over the station mark and the transit level or optical level is adjusted so that it is totally horizontal. Once the centering of the tripod is established, and the reference point is established, then the transit level can be used to see if a wall to be constructed is plumb, that is that it is in the true vertical position. Quite often in industrial parks the walls forming the sidewalls of a given building are made of cast concrete and are poured at the construction site. After the concrete has set for a sufficient period of time, the slabs forming the walls are raised and set into position. The plumb of the concrete slab forming part of the sidewall must be checked to make sure that it is in the true vertical, that is that the wall is plumb. In the known prior art, this can be done by a transit level which allows the telescope of the transit level to be moved up and down as well as sideways. The present invention is energized by means of a battery pack and the collimator laser source emitting an infrared beam is spun at such a high speed that it creates a vertical plane. This vertical plane of laser light is used as a reference to check the plumb of the slab forming the sidewalls. Electronic detection devices are used by the construction crew to determine that the wall slab is indeed plumb by means of checking it with reference to the laser plane.